Medical graft connector or plug structures, and methods of making and installing same

ABSTRACT

A medical graft connector or plug is made, for example, by cutting end portions of a tube of highly elastic material axially at numerous locations spaced circumferentially around the tube to produce a plurality of fingers which extend axially from each end of an uncut medial portion of the tube. The fingers are deflected radially outwardly from the medial portion and set in that condition. For a graft connector, the medial portion is coaxially connected to an end portion of a tubular graft. The connector is then installed through an aperture in the side wall of a patient&#39;s tubular body conduit, for example, by using a delivery tube in which the fingers are elastically deflected back to approximately their initial positions. When the delivery conduit is withdrawn from the connector, the fingers spring out to engage the inner and outer surfaces of the body conduit wall. For a plug, the medial portion is occluded and then the structure is installed through the aperture to be plugged in a manner similar to installation of the connector.

This application is a division of U.S. patent application Ser. No.09/569,607, filed May 10, 2000, which is a continuation of U.S. patentapplication Ser. No. 09/540,665, filed Mar. 31, 2000 (now U.S. Pat. No.6,391,036), which is a division of U.S. patent application Ser. No.09/016,721, filed Jan. 30, 1998 (now abandoned). All of these priorapplications are hereby incorporated by reference herein in theirentireties.

BACKGROUND OF THE INVENTION

This invention relates to structures that can be used to makeconnections between tubular medical grafts and a patient's tubular bodyconduits. The structures of the invention can alternatively beconstructed for use as medical plugs (e.g., to close atrial orventricular septal defects). The invention also relates to methods formaking and using the structures mentioned above.

Tubular grafts are frequently needed in medical procedures. For example,a coronary bypass procedure may involve the installation of a tubulargraft between an aperture that has been formed in the side wall of theaorta and an aperture that has been formed in the side wall of acoronary artery downstream from an occlusion or blockage in that artery.Each end of the graft must be connected to the side wall of either theaorta or the coronary artery. Each such connection must extend annularlyaround the associated end of the graft conduit and be fluid-tight sothat no blood will leak out. One common way to produce such connectionsis by suturing. It will be appreciated, however, that making suchconnections by suturing can be extremely difficult, time-consuming, anddependent on the skill of the physician for the quality of the results.There is also increasing interest in less invasive procedures which tendto impose constraints on the physician's access to the sites at whichgraft connections must be made and thereby make it more difficult oreven impossible to use suturing to make such connections (see, forexample, Goldsteen et al. U.S. Pat. No. 5,976,178, Sullivan et al. U.S.Pat. No. 6,120,432, and Sullivan et al. U.S. patent application Ser. No.08/869,808, filed Jun. 5, 1997, all of which are hereby incorporated byreference herein in their entireties). Various types of mechanicalconnectors have been developed to reduce or eliminate the need forsuturing, but improvements are constantly sought for such mechanicalconnectors with respect to considerations such as ease and speed of use,ease of manufacture, strength and permanence of the resultingconnection, etc.

Plugs are also needed in a variety of medical procedures. For example,it may be necessary to plug an atrial or ventricular septal defect inthe heart of a new-born child. Again, improvements are constantly soughtfor plugs which can be easily and quickly installed using minimallyinvasive procedures.

In view of the foregoing, it is an object of this invention to provideimproved and simplified graft connectors.

It is another object of this invention to provide improved andsimplified medical plugs.

It is still another object of this invention to provide improved andsimplified methods of making structures that can be used as eithermedical graft connectors or plugs.

It is yet another object of this invention to provide improved andsimplified methods for installing medical graft connectors or plugs.

SUMMARY OF THE INVENTION

These and other objects of the invention are accomplished in accordancewith the principles of the invention by providing a connector or plugstructure preferably formed by starting from a tube of highly elasticmaterial such as nickel and titanium alloy (nitinol) metal. Each endportion of the tube is cut substantially axially at numerous locationsspaced circumferentially around the tube to produce a plurality offingers that extend substantially axially from each end of a remainingmedial portion of the tube. The fingers at each end of the medialportion are then deflected so that they extend substantially radiallyout from the medial portion, and the fingers are set (e.g., by a heattreatment) in that deflected condition. For use of the structure as agraft connector, the medial portion is attached substantially coaxiallyto an end portion of a graft conduit. For use of the structure as a plugthe medial portion of the tube is filled with a suitable pluggingmaterial or structure.

To install the graft connector or plug in a patient the fingers at eachaxial end of the medial portion may be elastically deformed back towardtheir initial condition (in which the fingers extend substantiallyaxially from the ends of the medial portion). The structure may then beinserted in a delivery tube, which may maintain the fingers in theirsubstantially axially extending condition. The delivery tube may then beinserted through the aperture in the side wall of the patient's tubularbody conduit to which the end of the graft conduit is to be attached, orthrough the aperture in the patient's tissue structure that is to beplugged. The delivery conduit may then be removed from around theconnector or plug structure. This releases the fingers at each end ofthe medial portion to spring out on respective opposite sides of thetissue structure to which the connection is to be made, or to which theplug is to be applied.

In some cases fingers may only be formed in one end of a starting tube.A connector may then be provided using two such tubes concentric withone another and with a graft conduit. In such an assembly the fingers onthe two tubes extend from generally opposite axial ends of the assembly.Two such tubes may be similarly used to make a plug, although in thiscase the graft conduit is omitted and the interior of the structure isfilled with a plugging material or structure.

As an alternative or addition to use of a delivery tube to releasablyhold the fingers substantially parallel to the longitudinal axis of aconnector or plug, another structure may be removably placed around thefingers. Examples of such another structure include a collar or a strandof material such as wire or suture material.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an illustrative embodiment of astarting component for a structure of this invention.

FIG. 2 is an end elevational view of the component of FIG. 1.

FIG. 3 is a side elevational view of the FIG. 1 component after someprocessing in accordance with the invention.

FIG. 4 is a sectional view of the FIG. 3 component after furtherprocessing in accordance with the invention.

FIG. 5 is an end elevational view of the FIG. 4 component.

FIG. 6 is a simplified side elevational view of the FIG. 4 componentwith a graft conduit added so that the FIG. 4 component can be used as aconnector for the graft conduit.

FIG. 7 is a simplified, partly cut away, side elevational view of theFIG. 6 assembly in illustrative apparatus for use in installing the FIG.6 assembly in a patient.

FIG. 8 illustrates use of the FIG. 7 apparatus to install the FIG. 6assembly in a patient.

FIG. 9 is a simplified sectional view of the FIG. 4 component with plugmaterial or structure added so that the FIG. 4 component can be used asa plug.

FIG. 10 is a view similar to FIG. 7, but for the plug embodiment of FIG.9.

FIG. 11 is a view somewhat like FIG. 8, but for the plug embodiment ofFIGS. 9 and 10.

FIG. 12 is another view somewhat like FIG. 11, but showing a fullyinstalled plug of the type shown in FIG. 9.

FIG. 13 is another view similar to FIG. 3 showing an illustrativemodification of a FIG. 3 type structure in accordance with theinvention.

FIG. 14 is another view similar to a portion of FIG. 4 showing anillustrative modification of a FIG. 4 type structure in accordance withthe invention.

FIG. 15 is a sectional view somewhat like FIG. 8 showing illustrativemodifications in accordance with the invention.

FIG. 16 is a simplified sectional view showing still other illustrativemodifications in accordance with the invention.

FIG. 17 is a simplified sectional view showing an assembly similar tothe assembly shown in FIG. 6, but with an illustrative modification inaccordance with the invention.

FIG. 18 is a simplified sectional view somewhat like FIG. 4 which isuseful in explaining an illustrative modification in accordance withthis invention.

FIG. 19 is a view somewhat like FIG. 7 or FIG. 10 for the modifiedstructure of FIG. 18.

FIG. 20 is a simplified sectional view showing an illustrative precursorstructure for embodiments of the type illustrated by FIGS. 18 and 19.

FIG. 21 is a simplified elevational view showing another illustrativeprecursor structure for embodiments of the type illustrated by FIGS. 18and 19.

FIG. 22 is a simplified sectional view similar to FIG. 15 showing otherillustrative modifications in accordance with the invention.

FIG. 23 is a simplified elevational view similar to FIG. 3 showing moreillustrative modifications in accordance with the invention.

FIG. 24 is another simplified elevational view similar to FIG. 3 showingstill more illustrative modifications in accordance with the invention.

FIG. 25 is a simplified sectional view showing an illustrativealternative to apparatus of the type shown in FIG. 7.

FIG. 26 is a simplified elevational view illustrating another possiblemodification of structures in accordance with the invention.

FIG. 27 is a simplified elevational view somewhat like FIG. 3 showinganother illustrative embodiment of the invention.

FIG. 28 is a simplified sectional view illustrating use of apparatus ofthe type shown in FIG. 27.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An illustrative starting component for the connector or plug structuresof this invention is a hollow tube 10 as shown in FIGS. 1 and 2. Tube 10may have any length, diameter, and wall thickness suitable for theintended use of the finished connector or plug structure. For use as acardiac bypass graft connector, for example, tube 10 may have a diameterof about 4.0 millimeters, a wall thickness of about 0.003 inches, and alength of about 7.0 millimeters. It will be understood, however, thatthese specific dimensions are only exemplary, and that any otherdimensions can be used instead if desired. The material of tube 10 ispreferably highly elastic. A particularly preferred material is nickeltitanium alloy (nitinol) metal (which can be per se conventional), butother materials such as stainless steel or thermoplastics can be usedinstead if desired.

A first step in processing tube 10 in accordance with the invention isto cut into it substantially axially at many locations 12 spacedcircumferentially around each axial end portion as shown in FIG. 3. Cuts12 reduce starting tube 10 to a plurality of fingers 14 extendingsubstantially axially from each end of an uncut medial tube portion 16.Cuts 12 may be made by any suitable technique such as electron dischargemachining (“EDM”), laser cutting, or etching. The length of medialportion 16 may be selected based on the intended use of the structure.For example, the length of medial portion 16 may be selected tocorrespond to the thickness of the patient's body tissue through whichthe medial portion will extend. Illustrative lengths for medial portion16 are in the range from about 0.2 millimeters to about 4.0 millimeters.The length of fingers 14 may also be selected based on the intended useof the structure. Illustrative lengths for fingers 14 are in the rangefrom about 1.0 millimeter to about 10.0 millimeters.

The next step is to deflect fingers 14 to approximately the positionsthat it is desired for them to have in the finished and installedconnector or plug structure. For example, FIGS. 4 and 5 show deflectingfingers 14 substantially radially out from the end of medial portion 16that each finger is attached to. Although FIGS. 4 and 5 show the angle Abetween each finger 14 and the adjacent axially extending surface ofmedial portion 16 as approximately 90°, it will be understood that awide range of angles A (e.g., in the range from about 45° to about 120°)can be used. Indeed, the angle of deflection of various fingers 14 canbe different if desired. In addition, fingers 14 can be curved (e.g.,concave curved as viewed from a plane extending radially out from medialportion 16) rather than straight if desired, and indeed outwardcurvature of the fingers can be used in place of outward deflection by adefinite angle A. For example, the free ends of the fingers 14 at one orboth ends can curve toward or even overlap the free ends of the fingersat the other end. FIG. 6 and some subsequent FIGS. show examples of suchcurvature of fingers 14. FIG. 17 shows an example of overlapping fingers14. In general, however, fingers 14 will be deflected so that they haveat least a component of radially outward extension from medial portion16. For convenience and simplicity herein it will therefore sometimes besaid that fingers 14 extend radially out from medial portion 16, eventhough it will be understood that this wording includes (1) fingershaving only a component of such radially outward extension, and (2)fingers that are either substantially straight or curved.

It will also be appreciated that it may be desirable to deflect fingers14 beyond their desired final positions so that when they aresubsequently released during deployment, they will resiliently bear onthe tissue in which the connector or plug is installed in their effortto return to the positions to which they have been deflected in thisstep of their manufacture. For example, if FIG. 4 shows the desiredfinal position of fingers 14 in use in a patient (i.e., angle A=90°), itmight be desirable at this stage in the manufacturing process to deflectfingers 14 more than is shown in FIG. 4 (e.g., to angle A=60°) toincrease the security with which fingers 14 will engage tissuesurrounding medial portion 16. Nevertheless, for convenience andsimplicity herein it will sometimes be said that in this manufacturingstep fingers 14 are deflected to (or at least to) approximately theirintended final positions, it being understood that this wording includesdeflecting fingers beyond the actual intended final positions.

When fingers 14 have been deflected to approximately their finalintended positions (e.g., as shown in FIGS. 4 and 5), fingers 14 are setin those positions. For example, a heat treatment may be applied to thestructure to set fingers 14 in their deflected positions.

FIGS. 6-8 show use of a structure of the type shown in FIGS. 4 and 5 toprovide a connector 20 for an end of graft conduit 30. (The possiblealternative use of structures of the type shown in FIGS. 4 and 5 as aplug rather than a graft connector will be discussed after explanationof the connector embodiment is substantially complete.) Graft conduit 30may be natural conduit (e.g., a relocated portion of the patient'stubular body tissue), artificial conduit (e.g., of the type shown inabove-mentioned U.S. Pat. No. 5,976,178), or a composite of natural andartificial conduits.

In the illustrative embodiment shown in FIG. 6 an axial end portion ofgraft conduit 30 is inserted substantially coaxially into and attachedto medial portion 16. Depending on the materials of components 20 and30, they may be secured together by any suitable means such as suturing,adhesive, welding, etc.

The next step in use of the graft 30 and connector 20 is to insert thatassembly into a delivery tube 40 as shown in FIG. 7. Tube 40 ispreferably slightly larger in diameter than medial portion 16 or graftconduit 30. To fit structure 20 into tube 40 fingers 14 are resilientlydeflected back toward their initial positions as axial extensions fromthe ends of medial portion 16 as shown in FIG. 7. In other words,fingers 14 are elastically deflected inwardly toward parallelism with acentral longitudinal axis of medial portion 16. If connector 20 is madeof nitinol, temporary super-cooling of the connector may be used at thisstage to facilitate assembly of components 20 and 30 in delivery tube 40(assuming that graft conduit 30 can tolerate proximity to super-cooledconnector 20). Super-cooling nitinol makes it very plastic so thatfingers 14 can be straightened out and so that they will hold that shapefor insertion of components 20 and 30 into tube 40. When connector 20warms up again, it “remembers” the shape it was given during the step inwhich the fingers were set after being radially outwardly deflected.

The next step in use of the assembly shown in FIG. 7 is to insertdelivery tube 40 through an aperture in the side wall of the patient'stubular body conduit (50 in FIG. 8) to which graft conduit 30 is to beconnected by connector 20. For example, a tapered distal end portion ofdelivery tube 40 (shown on the right in FIG. 7) may be used to help tube40 enter the aperture in tubular body conduit side wall 52. Elements 20,30, and 40 are preferably positioned relative to side wall 52 so thatmedial portion 16 is approximately centered on side wall 52. This placesthe fingers 14 at one axial end of medial portion 16 inside conduit 50,while the fingers 14 at the other end of medial portion 16 are outsideconduit 50.

The next step is illustrated by FIG. 8 and involves the withdrawal ofdelivery tube 40 from the aperture in side wall 52, while components 20and 30 are held stationary relative to side wall 52. As delivery tube 40is thus withdrawn, the fingers 14 on the inside of conduit 50 aregradually released to resiliently spring out inside side wall 52 aroundthe aperture through that wall. Thereafter, as delivery tube 40continues to be retracted, the fingers 14 on the outside of conduit 50are also released to resiliently spring out outside side wall 52 aroundthe aperture through that wall. Thus the final condition of connector 20is as shown in FIG. 8 (although of course delivery tube 40 is ultimatelycompletely withdrawn from the patient). The fingers 14 on the inside ofconduit 50 prevent the connector and graft conduit from pulling out ofthe aperture in side wall 52. The fingers 14 on the outside of conduit50 prevent the connector and graft conduit from protruding undesirablyfar into conduit 50.

Although FIGS. 7 and 8 show inserting connector 20 into the aperture inthe side wall 52 of conduit 50 from outside that conduit, connector 20could alternatively be inserted from inside the lumen of conduit 50. Inthat case connector 20 would typically be located at a medial positionin delivery tube 40, with graft conduit 30 extending from the connectorin the distal direction along the interior of tube 40. Tube 40 wouldthen be inserted intraluminally into conduit 50 until the location ofthe aperture in wall 52 is reached. Tube 40 would then be passed out ofthe aperture in wall 52 until medial portion 16 is centered on wall 52.Components 20 and 30 would then be held stationary relative to conduit50 while tube 40 is pulled back proximally via the lumen of conduit 50,thereby exposing graft conduit 30 outside conduit 50 and similarlyexposing connector 20 so that fingers 14 can spring out and engage theinner and outer surfaces of side wall 52 around the aperture in thatside wall. A separate axially extending pusher or holder structure maybe needed inside tube 40 to help hold components 20 and 30 stationary asdescribed above while tube 40 is pulled back proximally.

FIG. 9 shows an alternative embodiment in which a structure of the typeshown in FIGS. 4 and 5 is adapted for use as a plug 60. In thisalternative medial portion 16 is substantially filled or occluded with aplug material or structure 70 such as silicone or thermoplastic. Plug 60is then inserted in a delivery tube 40 as shown in FIG. 10 insubstantially the same way that tube 40 is used with component 20 inFIG. 7.

The next step in the use of assembly 40/60 is to insert tube 40 throughthe aperture in the tissue structure 80 that is to be plugged as shownin FIG. 11. As in the previously described connector embodiment,assembly 40/60 is preferably positioned relative to tissue structure 80so that the fingers 14 extending from one axial end of medial portion 16are on one side of structure 80, and so that the fingers 14 extendingfrom the other axial end of medial portion 16 are on the other side ofstructure 80.

The next step is to withdraw tube 40 from the aperture in tissuestructure 80, while holding plug 60 substantially stationary relative tostructure 80. To hold plug 60 stationary in this manner, a holder tube(not shown) may be inserted into tube 40 until the distal end of theholder tube bears on plug structure 70. Then the holder tube can be heldstationary relative to tissue structure 80 while tube 40 is withdrawn.As tube 40 is withdrawn, the fingers 14 on the right-hand side ofstructure 80 as viewed in FIGS. 11 and 12 are gradually released tospring resiliently out against that side of structure 80. Furtherwithdrawal of tube 40 allows the fingers on the left-hand side ofstructure 80 to spring resiliently out against that side of structure80. The completed plug installation is as shown in FIG. 12.

As in the case of connector 20, plug 60 can be inserted into theaperture in tissue structure 80 from either side of that tissuestructure, and tube 40 can similarly be withdrawn in either direction.For example, if tissue structure 80 is the wall of a conduit or chamber,plug 60 can be installed from either the inside or outside of thatconduit or chamber, and tube 40 can be withdrawn via either the insideor outside of that conduit or chamber.

Manufacture of the connector or plug structures described above isgreatly facilitated by the fact that elements 14 and 16 all come fromone starting structure (i.e., tube 10). Elements 14 and 16 are thereforeintegral at all times, and there is no need to attempt to assemblerelatively small fingers 14 on another component. Use of the connectoror plug structures of this invention is extremely easy because all thatis required is to properly position the connector or plug relative tothe appropriate tissue of the patient and then withdraw the deliverytube 40 from around the connector or plug. Fingers 14 automaticallyspring out into the positions required to complete and secure theconnector or plug.

If desired, medial portion 16 can be perforated at any suitable timeduring the course of manufacturing a connector or plug in accordancewith this invention. For example, FIG. 13 shows many perforations 16 bin medial portion 16, thereby effectively reducing the medial portion toan open mesh of members 16 a. Such perforation of medial portion 16 mayincrease its flexibility (e.g., axially and radially) and therefore itslong-term acceptability in the patient's body. The radial compliance ofa flexible connector or plug (i.e. the ability of such a structure toresiliently increase or decrease in circumference) is believed to bebeneficial with respect to long-term body circuit lumen patency.Increased flexibility and radial compliance of medial portion 16 mayalso facilitate delivery and/or installation of the connector or plug.For example, flexibility of medial portion 16 may allow a connector orplug to be resiliently circumferentially compressed to a relativelysmall size to facilitate delivery of the connector or plug to aninstallation site (e.g., delivery through the lumen of a patient's bodyconduit). After the connector or plug has been delivered to the desiredsite in the patient's body in its circumferentially compressed size, theconnector or plug is released from the delivery apparatus so that it canautomatically return to its original larger size. In the case of aconnector for a natural tissue graft, perforation of medial portion 16may allow the tissue of the graft and conduit to which the graft isconnected to grow together through the perforations.

Perforation of medial portion 16 may also allow that portion of aconnector or plug to exert resilient, radially outward force onsurrounding tissue on a long-term basis after the connector or plug hasbeen installed. This may be useful for such purposes as firmerengagement of the surrounding tissue, reduced potential for fluidleakage around the connector or plug, etc. For example, if the elasticrecoil of the surrounding tissue diminishes over time or if the tissueis relatively non-elastic due to disease or age, sealing between thetissue and the connector or plug may be reduced. In such cases,resilient outward expansion of the connector or plug can be helpful incompensating for deficiencies of the tissue. A connector or plug with aperforated medial portion 16 can resiliently expand to fill any openingthat may otherwise tend to develop between portion 16 and thesurrounding tissue if and when the elastic recoil of the tissuediminishes.

Whereas the depicted connector and plug embodiments are round, othershapes (e.g., ellipses, polygons, etc.) are equally possible. Similarly,the ends of medial portion 16 do not have to be perpendicular to thelongitudinal axis of the connector or plug structure. Particularly inthe case of connectors, it may be desired to have one or both ends ofmedial portion 16 skewed relative to the longitudinal axis of theconnector (i.e., so that the longitudinal axis is not perpendicular to aplane defined by the skewed end of medial portion 16). The free ends ofthe adjacent fingers 14 may then be similarly skewed. Such skewing ofportions of the connector may facilitate connecting the end of a graftto the side wall of a patient's body conduit at an angle other than 90°to that side wall. These and other illustrative examples ofmodifications, alternatives, and enhancements in accordance with theinvention will now be discussed in more detail with reference to FIGS.14-28.

FIG. 14 shows that the free ends of fingers 14 can be sharply pointed asindicated at 14 a to facilitate engagement and or penetration of tissueby the fingers. This can be done, for example, by sharpening theassociated axial end of the starting tube 10 to a sharp annular edgeprior to making cuts 12 as shown in FIG. 3.

FIG. 15 shows the free ends of the fingers 14 that are generally on theinside of conduit 50 penetrating and passing through the conduit wall 52to more firmly secure connector 20 to conduit 50. In addition, FIG. 15shows that the free ends of the above-mentioned fingers 14 may beprovided with barbs 14 b (somewhat like the barbs on fishing hooks) thatstrongly resist withdrawal of the fingers after the fingers havepenetrated the tissue of conduit wall 52. FIG. 15 still further showsthat the fingers 14 on the inside of conduit 50 in a finished connectionmay be different from the fingers 14 on the outside of conduit 50. Forexample, the fingers 14 on the inside of conduit 50 may be longer,curved and sharply pointed for tissue penetration, and barbed as at 14b, while the fingers 14 on the outside of conduit 50 may be shorter,straighter, blunter, not barbed, and therefore not as adapted for tissuepenetration. Such differences between the inner and outer fingers 14 mayreflect different performance characteristics needed of them. Fluidpressure inside conduits 30 and 50 may attempt to force conduit 30 awayfrom conduit 50, thereby necessitating relatively strong inner fingers14. Concomitantly, there may be little tendency of conduit 30 to extendfarther into conduit 50, so that outer fingers 14 can be relativelyweak. Other differences that can be made between inner and outer fingers14 include differences in number, spacing, width, etc.

FIG. 16 illustrates a point made earlier; namely, that a connector orplug in accordance with this invention can have a cross sectional shapeother than round. In the particular example shown in FIG. 16 theconnector or plug has an elliptical cross section, with the major axisof the ellipse substantially aligned with the longitudinal axis ofconduit 50. In addition, FIG. 16 shows that different fingers 14 ateither or both axial ends of medial portion 16 can have differentlengths. In the particular example shown in FIG. 16 the fingers 14 thatare more nearly aligned with the longitudinal axis of conduit 50 arelonger than the fingers that are more nearly perpendicular to thelongitudinal axis of conduit 50. To produce fingers 14 of differentlengths, one or both axial ends of the starting tube 10 can beappropriately shaped prior to making cuts 12, or the free ends of thefingers can be trimmed after cuts 12 have been made.

FIG. 17 illustrates another possibility mentioned earlier; namely, thatthe fingers 14 extending from axially opposite ends of medial portion 16may be deflected and set so that their free ends overlap. When aconnector or plug made in this way is installed in a patient, thisconstruction of fingers 14 helps to increase the contact area betweenfingers 14 and the tissue between them, as well as compression of thetissue between the fingers.

It may desirable to make fingers 14 so that their flexural stiffness(especially in directions radial of medial portion 16) varies in apredetermined way along the length of each finger. This feature can beused, for example, to cause the fingers to assume a more nearlycylindrical shape when they are deflected for insertion into a deliverytube 40. Thus FIG. 18 shows a connector or plug which makes use of thispossible feature prior to insertion into a delivery tube, and FIG. 19shows the FIG. 18 structure after insertion into delivery tube 40. Acomparison of FIG. 7 or 10, on the one hand, with FIG. 19, on the otherhand, reveals that in FIG. 19 fingers 14 form a more nearly cylindricalarray at each axial end of medial portion 16 because the flexuralstiffness of the fingers in FIGS. 18 and 19 has been tailored to producethis result.

FIGS. 20 and 21 show illustrative techniques for tailoring the flexuralstiffness of fingers 14 along their length as mentioned above inconnection with FIGS. 18 and 19. In FIG. 20 the thickness of the wall ofthe starting tube 10′ is varied along the length of the tube to givefingers 14 correspondingly varied thickness along their lengths. In FIG.21 fingers 14 are cut so that their width varies along their length. Ifdesired both techniques (FIG. 20 and FIG. 21) can be combined. Ingeneral terms, the geometry of fingers 14 can be tailored in anysuitable way to cause fingers 14 to exhibit any desired elasticbehavior.

FIG. 22 illustrates another technique for attaching natural orartificial graft conduit 30 to a connector in accordance with thisinvention. As shown in FIG. 22 the fingers 14 at one end of medialportion 16 are made to pass through (e.g., by piercing) an annular endportion of graft conduit 30. When the connector and graft are installedin the patient through an aperture in the patient's body tissue wall 52,these fingers 14 curve back to contact one surface of wall 52, while thefingers 14 at the other end of medial portion 16 curve back to contactthe other surface of wall 52.

FIG. 23 illustrates another point that has already been mentionedbriefly; namely, that an end of a connector of this invention can havean angle other than 90° to the longitudinal axis of the connector. Inthe example shown in FIG. 23 the left-hand end of the connector is notperpendicular to the longitudinal axis of the connector. This type ofconnector may be particularly suitable for connecting a graft conduit tothe sidewall of another conduit at an angle which is not perpendicularto the longitudinal axis of the other conduit.

FIG. 24 illustrates a technique that may be used to releasably holdfingers 14 in a desired configuration prior to deployment of a connectoror plug in a patient. In this embodiment the free end portion of eachfinger 14 near one end of the connector or plug has a hole 14 c throughit. A wire 90 or other suitable material strand is threaded throughthese holes and formed into a loop that holds the fingers in a desiredcondition (in this case, a substantially cylindrical extension of medialportion 16). When loop 90 is undone and pulled out of holes 14 c, theassociated fingers 14 are released to spring radially out (e.g., asshown in FIG. 8 or FIG. 12). This type of releasable retention offingers 14 can be used in place of or in addition to retention inside adelivery tube (e.g., tube 40 in FIG. 7 or 10) to facilitate control ofthe associated fingers until it is desired to fully deploy them. Forexample, such releasable confinement and control of fingers 14 may beuseful to facilitate intraluminal delivery and deployment of a connectoror plug.

FIG. 25 shows another example of a structure 100 for releasablyconfining fingers 14 on a connector. In this case structure 100 is anelongated tube or rod which extends axially through the connector. Asomewhat enlarged head 102 on one end of structure 100 includes a recess104 for releasably receiving the free ends of the fingers 14 at one endof medial portion 16. In other words, recess 104 defines a collar 106that extends annularly around the adjacent free ends of fingers 14. Whenfingers 14 are thus received in recess 104 or collar 106, they areprevented from springing radially outwardly. However, when fingers 14are released from recess 104 or collar 106 (e.g., by shifting structure100 to the left relative to the other elements shown in FIG. 25), thefingers are free to resiliently spring radially outwardly. Structure 100can then be removed (e.g., by pulling it back to the right as viewed inFIG. 25). Head 102 may additionally be sharply pointed as shown in FIG.25 to act as an incisor and/or dilator for helping the structure to passthrough a patient's body tissue wall prior to release of fingers 14 fromrecess 104 or collar 106. Structure 100 may be adapted for passage intoa patient along a guide wire previously installed in the patient. Forexample, structure 100 may have a central, axially extending bore orlumen through which such a guide wire may pass. A central, axiallyextending guide structure may similarly be used with embodiments likethe one shown in FIG. 7.

FIG. 26 shows possible modification of a connector in accordance withthe invention to include a web 110 of a highly elastic material such assilicone between adjacent fingers 14. Such a web 110 can be provided onthe fingers 14 at either or both ends of medial portion 16. Possiblebenefits of web 110 include enhanced sealing and faster clotting. Ifdesired, a clot-enhancing or clot-promoting material or drug can beadded to web 110.

Although not always specifically mentioned above, it will be understoodthat many of the features shown in FIGS. 14-26 are applicable to plugsas well as to graft connectors.

FIGS. 27 and 28 show an alternative embodiment in which a connector isassembled from two initially separate parts 10 x and 10 y. Each of parts10 x and 10 y is preferably formed from a tube similar to the tube shownin FIGS. 1 and 2. The diameter of the tube used to form part 10 y issomewhat larger than the diameter of the tube used to form part 10 x.Fingers 14 x and 14 y are formed in one axial end portion of each tube.Holes 120 x and 120 y are formed in the other axial end portion of eachtube. A medial portion 16 x and 16 y remains in each tube between thefingers 14 and the holes 120 of that tube. The fingers 14 on each tubeare treated as described above for other embodiments (i.e., the fingersare deflected radially out and set in that condition).

Structures 10 x and 10 y are then assembled on an end of a graft conduit30 as shown in FIG. 28. In particular, the perforated and medialportions of structure 10 y are placed substantially concentricallyaround the outside of graft conduit 30, while structure 10 x is placedsubstantially concentrically inside the graft conduit. Structures 10 xand 10 y are oriented so that their fingers 14 are oppositely directedalong the longitudinal axis of graft conduit 30. Structures 10 x, 10 y,and 30 are secured together (e.g., by sutures 130 through radiallyadjacent holes 120 x and 120 y and the intervening wall material ofconduit 30). As an alternative or addition to suturing, structures 10 x,10 y, and 30 may be press fit together, and/or an adhesive may be usedto help hold these components together. Fingers 14 may be resilientlydeflected substantially parallel to the longitudinal axis of conduit 30and away from the region of holes 120 if that will facilitate assemblyof structures 10 x and 10 y on conduit 30. The assembly of structures 10x, 10 y, and 30 may be delivered to and installed at a graft site in apatient in the same manner as is described above for any of the otherconnector embodiments.

Connectors of the type shown in FIGS. 27 and 28 may have the advantagethat, even though one component 10 x is inside conduit 30, thatcomponent can be radially recessed into conduit 30 as indicated at 30 x,thereby leaving a substantially smooth passageway for fluid flow throughconduit 30 and the connector. Such a smooth passageway is desirable forsuch purposes as avoiding any obstruction or disturbance (e.g., bycausing turbulence) of the fluid flow. The recessing at 30 x can beproduced by clamping the tissue between the tubular portions ofcomponents 10 x and 10 y.

In some applications it might be possible to use only one structure like10 x or 10 y in a graft connector. For example, it might be possible toeliminate structure 10 y from FIG. 28. In addition, if structure 10 y iseliminated from FIG. 28, the assembly shown in FIG. 28 could be furthermodified by placing structure 10 x outside rather than inside the end ofgraft conduit 30. Any of the modifications and/or enhancements describedabove for other connector embodiments can also be applied to connectorsof the type shown in FIGS. 27 and 28.

Structures of the type shown in FIGS. 27 and 28 are also usable to makeplugs in accordance with this invention. For example, a structure like10 x may be assembled with a structure like 10 y generally as shown inFIG. 28, but without graft conduit 30. The interior of the assemblywould be occluded by a plugging material or structure, generally asshown at 70 in FIG. 9, to produce a completed plug. Such a plug would beinstalled as described above for any of the other plug embodiments.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that still other modifications can bemade by those skilled in the art without departing from the scope andspirit of the invention. For example, the various materials anddimensions mentioned herein are only examples, and other materials anddimensions can be used if desired. As another example of modificationswithin the scope of the invention, as an alternative to starting with atube like tube 10 in FIGS. 1 and 2, one could start with a web of anymaterial that would be suitable for tube 10. Two opposite marginalportions of the web would then be cut at numerous substantially parallellocations (somewhat like cuts 12 in FIG. 3), leaving an uncut medial webportion. Medial web portion would then be formed into a medial tubeportion (like 16 in FIG. 3), e.g., by forming it around a mandrel, withor without bonding of the resulting seam. The structure would then besubstantially as shown in FIG. 3 and could be further processed and usedto produce a connector or plug as described above in connection with anyof the subsequent FIGS. Similar web rather than tube starting structurescould be used for embodiments of the type shown in FIGS. 27 and 28.

1. A device for use in closing septal defects comprising: a medialportion having a longitudinal axis, wherein the device is formed from ahollow tube; and first and second sets of fingers, wherein: at least oneof the first and second sets of fingers are formed from cuts spacedcircumferentially around the hollow tube; each set of fingers is capableof extending substantially radially outward from the axis; the first setof fingers is unconnected to the second set of fingers at the radiallyoutward ends; the first set of fingers is spaced an axial distance apartfrom the second set of fingers on the axis; and only one set of fingersis covered by a web of material between adjacent ones of the fingers. 2.The device of claim 1 wherein the uncovered set of fingers has freeends.
 3. The device of claim 1 wherein the fingers are resilientlybiased to extend substantially radially outward from the axis.
 4. Thedevice of claim 1 wherein the fingers comprise nitinol.
 5. The device ofclaim 1 wherein the web of material is elastic.
 6. The device of claim 5wherein the web comprises silicone.
 7. An installation assembly forinstalling the device of claim 1 comprising a delivery structuredisposed around the device substantially coaxial to the axis of themedial portion, whereby the fingers are elastically deflected inwardlytoward parallelism with the axis.
 8. The device of claim 1 wherein eachfinger has different thickness along its length.
 9. The device of claim1 wherein each finger has different width along its length.
 10. Thedevice of claim 1 wherein each finger has different flexural stiffnessradially of the medial portion along its length.
 11. The device of claim1 wherein the fingers are configured to elastically deflect towardparallelism with the axis.
 12. The device of claim 11 wherein the setsof fingers are configured to deflect in opposite directions and awayfrom each other.
 13. The device of claim 1 wherein the cuts aresubstantially axial in the hollow tube.
 14. The device of claim 1wherein the device comprises nickel titanium alloy.
 15. The device ofclaim 1 wherein the device comprises stainless steel.
 16. The device ofclaim 1 wherein the device comprises a thermoplastic.
 17. The device ofclaim 1 wherein the device is elastic.